Mixing valves are generally used to mix a warmer fluid (hereinafter referred to as the “hot” fluid) with a cooler temperature fluid (hereinafter referred to as the “cold” fluid) to deliver a fluid at a desired temperature. Frequently the fluid being mixed is water. The fluid exiting the mixing valve is frequently at a temperature between the hot fluid and the cold fluid. However, the valve may also deliver fluid at a temperature equal to either the hot or cold fluid under various circumstances, such as when the hot fluid is at a temperature less than the desired temperature or the cold fluid is at a temperature greater than the desired temperature. Mixing valves optionally include fail-safe mechanisms that permit operation of the mixing valve in the event of certain failures. Some mixing valves include thermostats to automatically control the temperature of the fluid exiting the mixing valve, and can also include various fail-safe devices to prevent undesirable situations, such as thermostat failures. Example uses for temperature-controlled mixing valves include emergency eyewash stations and various water delivery fixtures in hospitals to prevent scalding.
Mixing valves typically include a hot fluid inlet, a cold fluid inlet and a mixing chamber that mixes the hot and cold fluid. However, hot and cold fluid have a tendency to remain separate unless mixing is induced within the valve assembly, which can be difficult to achieve in the relatively small amount of space available for mixing within a typical valve assembly.
What is needed are improvements in thermostatically controlled valves that provide improved mixing of hot and cold fluids. Various embodiments of the present invention do this in novel and unobvious ways.